Loader pawl positioner



Nov. 26, 1963 c. 'r. JOHNSON ETA]. 3,111,911

LOADER FZAWL POSITIONER Filed June 27, 1962 4 Sheets-Sheet 1 INVENTORS CARL JOHNSON PALMER 6; WERMAGEI? WWW ATTORNEY 1963 c. 'r. JOHNSON ET AL 3,

LOADER PAWL POSITIONER 4 Sheets-Sheet 2 Filed. June 27, 1962 C. T. JOHNSON EI'AL Nov. 26 1963 LOADER PAWL POSITIONER 4 Sheets-Sheet 3 Filed June 27, 1962 o POSITIONERQ LINKAGE 3 m N T O M F. FIN E K O Wm CT MC mwm m m HR mw mB TN- wN NV PH M. l ,4 g

963 c. 'r. JOHNSON EIAL 3,111,911

LOADER PAWL POSITIQNER Filed June 2' 1962 4 Sheets-Shed 4 United States Patent 3,111,911 LOADER PAWL POSITIONER Carl T. Johnson, Minneapolis, and Palmer G. Wermager,

Robbinsdale, Minn., assignors, by mesne assignments,

to the United States of America as represented by the Secretary of the Navy Filed June 27, 1962, Ser. No. 205,806 2 Claims. (Cl. 104-172) This invention pertains generally to a loader trunk conveyor system, and more specifically the invention pertains to a new and novel structure and arrangement of parts thereof whereby a conveying chain accurately positions an article, such as a missile weapon, by mechanism independent of its drive sprocket. shrdlucmfwymm The transfer of an article, such as a missile weapon, from a hoist to a conveyor trunk involves a mating of the article supporting shoe lugs with the skid tracks of the loader. To provide the necessary mating accuracy during the transition period, a floating track mechanism is provided. This mechanism is the subject of a co-pending US. patent application entitled Floating Tracks, invented by Carl T. Johnson, John S. Scheurich, Sr., and Palmer G. Wermager, Serial No. 186,284, filed April 9, 1962, now Patent No. 3,086,480.

A short stroke of lateral force is necessary to disengage the raised article from the hoist and engage it with the floating tracks. The accuracy of this stroke or positioning is beyond the capability of the loader drive mechanism.

Accordingly, it is an object of the present invention to provide a positioner mechanism for rapidly and accurately shifting a booster shoe between two spaced positions.

Another object of this invention is to provide a positioner mechanism for both extending and retracting a booster shoe from the hoist to the loader floating tracks.

Another object of this invention is to provide safety interlocks associated with said positioner mechanism to permit actuation thereof only when said hoist and loader tracks are properly positioned.

These and other objects and attendant advantages of this invention will become more readily apparent and understood from the following detailed specification and accompanying drawings in which:

FIG. 1 is a perspective view of a loader pawl positioner incorporating features of this invention and showing a chain in buckled position and a pawl engaging a support shoe on an article;

FIG. 2 is a schematic diagram illustrating the hydraulic operation of the piston of the loader pawl positioner;

FIG. 3 is a perspective view of the linkages in a centering pin bracket assembly;

FIG. 4 is a cutaway perspective view of a positioner piston and interlock valve in a valve block; and

FIG. 5 is a cutaway view of a valve block showing the solenoid operated pilot valve, the metering valve and directional valve.

Referring now to the details of the drawings and particularly to FIGS. 1 and -2, the receiving end portion of an overhead conveyor tramway or loader is shown. By hoist mechanism (not shown) lug-geld articles 12, such as a missile weapon, are raised to this end of the loader 10 and are engaged by support shoes 14 to its rails 16.

A floating track 18 is provided which consists of a short, limited freedom, extended end section of the rails 16. These floating tracks 18 and rails 16 are contoured to receive and support the shoe 14 when the article 12 is thrust into engagement therewith and while propelled therealong by a loader chain 20.

The end of the loader chain 20 is equipped with a "ice pawl 22 through which the drive force of the chain 20 is applied to the shoe 14. Both the pawl 22 and the chain 20 are provided with side rollers 24 which travel in a chain track 26 of the rails 16 to prevent their buckling in thrust. The chain track 26 commences before the ends of the rails 16- and the floating track 18 and extends as far back as the chain drive sprocket 32 shown in FIG. 2, except for a short intermediate section of positioner track 28.

This positioner track 28 diflers from the chain track 26 by being pivoted at the aft end so that the forward end can be raised. The forward end of the positioner track 28 is pinned to an adjustable T-link 30 of a centering pin bracket assembly 34 which extends below the loader 10 as shown in FIGS. 2 and 3.

A wishbone yoke 36 is rotatably positioned on bearings 38 in this bracket assembly 34, and it is pivotally pinned in a buckling joint arrangement to the adjustable T-link 30. At this point, there is also pivoted a clevis 40 which, in turn, is pinned to a piston 42.

A valve 44 is connected to a spring-loadedlinkage 46, which extends to the underside of the loader chain 20. When the chain 20 is retracted by the sprocket \32 as far as permitted by a chain stop 48, as shown in FIG. 1, an interlock valve and switch actuator 50 moves the linkage 46 and shifts the valve 44.

A hydraulic control valve block 52 is bolted to the aft face of the centering pin bracket assembly 34. The previously mentioned piston 42 and valve 44 extend from this valve block 52 as shown best in FIG. 4. A loader positioner solenoid assembly 54 is mounted below the valve block 52 as shown in FIG. 5. This solenoid assembly 54 operates a pilot valve 56.

The shifting of valve 44 as related, ports hydraulic pressure fluid to this pilot valve 56. In case the loader pawl 22 and the chain 20* are not fully retracted to a position in which the positioner track can operate, hydraulic pressure fluid from a rail loaded indicator 58, as shown in FIG. 2, to the pilot valve 56 is blocked by the interlock valve 44, and the pressure port to pilot valve 56 is opened to tank instead.

The rail loaded indicator 58 is mounted close to a forward shoe floating track 7 0 with which it is associated. The rail loaded indicator 58 contacts the forward shoe 72 of the article 12 whether it is in the receiving recess of the floating track 70 and on the hoist mechanism or whether the shoes 14 and 72 have been positioned forward into the rails 16 and the hoist mechanism is down.

When the rails 16 are empty, the indicator 58 ports hydraulic pressure to the valve block 52 to permit the extension or retraction of the loader pawl 22. If the rail 16 is loaded but the hoist mechanism is down, the floating track 70 also is down and the indicator 58 blocks the hydraulic pressure fluid, thus preventing either extension or retracting of the pawl 22. With the rail 16 loaded and the hoist mechanism down, retracting the loader pawl would drop an article 12.

With full retraction of the chain 20 and with the indicator 58 indicating a loaded rail 16 with the hoist mechanism up, hydraulic fluid under pressure is available at the center land of pilot valve 56. Energizing solenoid assembly 54 to shift pilot valves 56 toward the solenoid will initiate a loader pawl retract cycle by shifting directional valve 60 and withdrawing latch valve 64, thereby releasing actuator piston 42. Piston velocity is controlled by a metering valve 62. As piston 42 extends, it straightens the previously described wishbone yoke 36 and the T-link 30 lifts the positioner track 28.

The positioner track next engages the chain 20 at a double width roller 68, shown in :FIG. 2, buckling two links of the chain 20. Since the chain 20 is held stationary at sprocket 32, this action draws the pawl 22 back a predetermined distance over the waiting shoe 14 of the article 12 to engage its fore and aft sides.

Next, retraction of the piston 42 straightens the chain 20, with pawl 22 moving forward to shove the article 12 so that its shoes 14 and 72 engage their respective floating tracks 18 and 70', and the article 12 is disengaged from the hoist mechanism for further movement along the loader 10 when the chain 22 is driven by the sprocket 32.

Obviously many modifications and variations of the present invention are possible in light of the above teachings. It is, therefore, to be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described.

What is claimed is:

1. In a conveyor apparatus having a chain driven article engaging member, a link chain, an elongated article supporting rail comprising a chain retaining track along the entire length of said rail, said chain and article engaging member being movable along said track between a normally retracted position in proximity to one end of said rail and an extended position remotely spaced along said rail from said retracted position, a rail section normally disposed intermediate the ends of and in alignment with said rail, said rail section being pivotally mounted at one end thereof for rotation out of alignment with said 4 rail to effect a buckling of the chain links associated therewith thereby to reduce the effective length of said chain and effect a retraction of said article engaging member.

2. In a conveyor apparatus having a chain driven article engaging member, a link chain, an elongated article supporting rail comprising a chain retaining track along the entire length of said rail, said chain and article engaging member being movable along said track between a normally retracted position in proximity to one end of said nail and an extended position remotely spaced along said rail from said retracted position, a rail section norm-ally disposed intermediate the ends of and in alignment with said rail, said rail section being pivotally mounted at one end thereof for rotation out of alignment with said rail, a hydraulic piston means operatively connected to said rail section whereby when said hydraulic piston means is actuated said rail section is rotated about its pivoted end causing said chain to buckle and thereby reduce the elfeotive length of said chain and effect a retraction of said article engaging member.

References Cited in the file of this patent UNITED STATES PATENTS 2,612,847 Burrows Oct. 7, 1952 

1. IN A CONVEYOR APPARATUS HAVING A CHAIN DRIVEN ARTICLE ENGAGING MEMBER, A LINK CHAIN, AN ELONGATED ARTICLE SUPPORTING RAIL COMPRISING A CHAIN RETAINING TRACK ALONG THE ENTIRE LENGTH OF SAID RAIL, SAID CHAIN AND ARTICLE ENGAGING MEMBER BEING MOVABLE ALONG SAID TRACK BETWEEN A NORMALLY RETRACTED POSITION IN PROXIMITY TO ONE END OF SAID RAIL AND AN EXTENDED POSITION REMOTELY SPACED ALONG SAID RAIL FROM SAID RETRACTED POSITION, A RAIL SECTION NORMALLY DISPOSED INTERMEDIATE THE ENDS OF AND IN ALIGNMENT WITH SAID RAIL, SAID RAIL SECTION BEING PIVOTALLY MOUNTED AT ONE END THEREOF FOR ROTATION OUT OF ALIGNMENT WITH SAID RAIL TO EFFECT A BUCKLING OF THE CHAIN LINKS ASSOCIATED THEREWITH THEREBY TO REDUCE THE EFFECTIVE LENGTH OF SAID CHAIN AND EFFECT A RETRACTION OF SAID ARTICLE ENGAGING MEMBER. 